Answer: C. 189 cm²
Step-by-step explanation:
A rectangle/square is solved for with A = L * W.
The middle square has a (surface) area of:
7 * 7 = 49 cm²
We then have four triangles. These are solved for with [tex]\frac{B*H}{2}[/tex]. Since all four are congruent, I will multiply one of them by 4.
The triangles have a total (surface) area of:
10 * 7 = 70
70 / 2 = 35
35 * 4 = 140 cm²
Lastly, we will add the two totals together.
140 cm² + 49 cm² = 189 cm²
The object has a surface area of C. 189 cm².
